How to parse xml files in Java or how to read xml files in java is one of common need of a Java Developer working with an enterprise Java application which uses XML for data representation, messaging, and data transfer. Java has good support to handle XML files and XML Documents and you can read XML Files in Java, create or write to XML file in Java by using various XML parsers available. Reading XML file is a little bit different than reading text or binary files in Java but it uses the same concept of File class.
Universal acceptability of XML and Java has helped them to grow together and they have a lot of things common in between just like Java is platform independence, XML provides data that is also platform-independent. You can use XML to transfer data between a legacy application written in C or C++ and Java.
What is important to work with XML in Java is the correct understanding of XML Parser, Basic knowledge of XML documents, etc. In this Java XML Tutorial, we will see how to parse an XML File by using both DOM XML Parser.
We will also see the difference between DOM and SAX parser in XML and other basics related to XML parsing in Java. I thought about this article after sharing my XPath notes in Java.
How to read XML File in Java
Here are a couple of ways to parse an XML file in Java. You will learn how to use JAXP and DOM parser to load the XML file in Java
1. JAXP - Java API for XML Parsing
Java provides extensive support for reading XML file, writing XML file and accessing any element from XML file. All XML parsing related classes and methods are inside JAXP. Though DOM related code comes from org.w3c.dom package. All XML parsers are in javax.xml.parsers package.we will see example of parsing xml files using JAXP API in next section.
2. Parse XML File in Java using DOM Parser
In this section, we will see how to parse xml files or how to read xml file using DOM XML Parser.DOM is a quick and easy way to parse xml files in Java and if you are doing it for testing its way to go.
The only thing to concern is that XML files that need to be parsed must not be too large. You can also create xml file by using DOM parser and DocumentFactory Class in Java.
The only thing to concern is that XML files that need to be parsed must not be too large. You can also create xml file by using DOM parser and DocumentFactory Class in Java.
XML file for parsing in Java
Here is xml file Stocks.xml which contains some stocks and there price, quantity we will use this in our xml parsing example in Java.
<?xml version="1.0" encoding="UTF-8"?>
<stocks>
<stock>
<symbol>Citibank</symbol>
<price>100</price>
<quantity>1000</quantity>
</stock>
<stock>
<symbol>Axis bank</symbol>
<price>90</price>
<quantity>2000</quantity>
</stock>
</stocks>
3. Code Example of Parsing XML File in Java using DOM Parser
Here is a code example of parsing above xml file in Java using DOM parser:
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class DOMExampleJava {
public static void main(String args[]) {
try {
File stocks = new File("Stocks.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(stocks);
doc.getDocumentElement().normalize();
System.out.println("root of xml file" + doc.getDocumentElement().getNodeName());
NodeList nodes = doc.getElementsByTagName("stock");
System.out.println("==========================");
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element element = (Element) node;
System.out.println("Stock Symbol: " + getValue("symbol", element));
System.out.println("Stock Price: " + getValue("price", element));
System.out.println("Stock Quantity: " + getValue("quantity", element));
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
private static String getValue(String tag, Element element) {
NodeList nodes = element.getElementsByTagName(tag).item(0).getChildNodes();
Node node = (Node) nodes.item(0);
return node.getNodeValue();
}
}
Output:
root of xml file stocks
==========================
Stock Symbol: Citibank
Stock Price: 100
Stock Quantity: 1000
Stock Symbol: Axis bank
Stock Price: 90
Stock Quantity: 2000
That’s all on xml parsing in java for now. We have seen how to read and write xml files in Java and are now familiar with both DOM and SAX Parser in java. We will see more on xml in the coming days like reading xml elements via XPath and using xml beans etc. let me know if you have any doubt on xml parsing examples or in general with xml and Java.
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21 comments :
Hi,
I really liked your post, can you please cover something about JAXB, XStream, Jibx also, it will be very useful
Thanks Anonymous, I would definitely try to cover more about JAXB, Xstream, Xerces etc.